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using pre-operative radiation therapy. Patients had to have an operable tumor and no evidence of distant metastases. The majority of the tumors were fairly extensive and displacing abdominal organs. All patients were treated with megavoltage radiation with IMRT delivery. A minimum dose of 45 Gy was delivered to full volume with a margin to the PTV. An SIB was delivered to the GTV or the high dose areas to a dose of 55 GY all in 25 Daily Fractions. Surgery followed 4-6 weeks later. Results: During the period of 2011 to 2014, 23 patient s have been treated. The use of IMRT has facilitated dose delivery and escalation in a safe manner. The patterns of toxicity including bowel symptoms and delayed healing have been compared with historical controls. None of our patient has developed any significant acute toxicity necessitating stopping radiation therapy. No severe late effects have been reported. Despite the large volume treatment surgical resections have been successful in all patients. Follow-up is ranging from 6 months to 4 years. Detailed toxicity analysis will be presented at the meeting. Conclusion: Dose escalation and dose delivery to a large abdominal volume are safe and feasible in RP Sarcomas with the use of IMRT. Acute and subacute side effects are limited and much less than historical controls. It remains to be seen if that will translate into long term improvement in survival.

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whose tumor volume was less than 5.0 cm 3 (p Z 0.001). This relationship was independent of T stage (p Z 0.03) and did not vary by tumor subsite (pZ0.08). For T1-2 tumors less than 5.0 cm 3 , 5-and 10-year local control rates were 98% and 90%, respectively. For T1-2 tumors greater than or equal to 5.0 cm 3 , 5-and 10-year local control rates were 77% and 64%, respectively. For T3 tumors, 5-and 10-year local control rate was 84% if less than 5.0 cm 3 and 71% if greater than or equal to 5.0 cm 3. Only 1 patient had a T4 tumor less than 5.0 cm 3 who did not fail locally. T4 tumors greater than or equal to 5.0 cm 3 achieved local control of 74% at both 5 and 10 years. Overall survival was not significantly different by tumor volume. Six patients developed soft tissue necrosis, and 2 patients suffered fatal carotid blowouts. All patients with severe complications, grade 5 CTCAE complications, were treated with concomitant chemotherapy. Four patients (2%) required total laryngectomy for a non-functional larynx, fourteen (8%) additional patients went on to require a permanent tracheostomy or permanent gastrostomy tube. Conclusion: Calculation of pretreatment primary tumor volumes, as defined on high-quality pretreatment CT imaging, can be useful in identifying patients most likely to experience local control with definitive radiotherapy or combined chemoradiation. Local control for SCC of supraglottic larynx is optimal if the primary tumor volume is less than 5.0 cm 3 .

Following radiotherapy, PSA nadir is correlated with disease-free survival-lower nadir predicting higher long-term biochemical disease-free rates; however, temporary PSA rise ("bounce") may confound this prediction. We present mature results from a prospective Phase II SBRT trial correlating PSA response kinetics with relapse, with detailed analysis of patients with any post-SBRT PSA rise. Materials/Methods: 17 institutions treated 259 low-and intermediate-risk patients with SBRT (38Gy/4 fx) with median and maximum post-SBRT follow-up of 5 and 8 years. "Heterogeneous" dosimetry was required: Dmax >150% of prescribed (Rx isodose 50-67%), with strict "HDR-like" urethra, bladder and rectal dose limitation. Androgen deprivation therapy was not used. Patients were considered biochemically relapsed if either Phoenix or ASTRO criteria were met. Results: Median PSA levels measured 5.12 ng/mL pre-SBRT and 0.9, 0.2, 0.1 and 0.055 ng/mL at 1, 3, 5 and 7 years post-SBRT, respectively. Although 93.2% of patients remained disease-free at 5-and 7-years (100% low risk, 88.5% int. risk; nadir + 2), only 35% (90/259) had continuously decreasing PSA values post-SBRT, while 65% (169/259) had at least one rise (median 0.2 ng/mL; range 0.1-4.2 ng/mL). Of patients with any post-SBRT PSA rise, only 15/169 (8.9%) developed confirmed biochemical relapse (CBR), while 154/169 (91.1%) remained disease-free. Among patients with any PSA rise, those with CBR had a higher median PSA nadir (2.2 vs 1.2 ng/mL for non-relapsers, pZ0.046), and shorter median time to 1 st rise (16 vs 23 months for non-relapsers, pZ0.03). Median magnitude of first PSA rise was similar: 0.2 ng/mL for both. Among patients with any PSA rise, additional factors associated with relapse are in the Table. Conclusion: After heterogeneous SBRT, median PSA decreases through 7 years of follow-up, reaching <0.1 ng/mL after year 6. Nearly 2/3rds of patients experienced at least one post-SBRT PSA rise, with over 90% remaining disease-free thereafter. PSA rise associated with biochemical relapse tended to occur sooner and have a higher pre-bounce nadir level and was also more commonly seen in older patients and those with nonlow-risk disease. These results may help physicians to better sort patients whose post-SBRT PSA rise is unlikely to portend relapse versus those who may require more intensive monitoring.